A. It is important that the Mezuzah be placed in a cover in order to prevent the name of G-d from being worn out over the course of time from being constantly touched and kissed, thereby transgressing the commandment not to erase the name of G-d. Therefore it is not a good idea to purchase Mezuzah covers with the name Sha-dai written on the outside, because even though it is not written with ink on parchment it is still forbidden to be erased.The Mezuzah should be permanently affixed to the doorpost. To do this, it is best to use nails or screws, but if necessary, you may also use glue or double-sided mounting tape. Regular scotch tape or masking tape, which are temporary adhesives, should not be used.When putting up Mezuzahs for more than one doorway in a house, only say the blessing once. When reciting the blessing, keep in mind the other doorways and the blessing will include all those Mezuzahs. We refrain from talking, or other interruptions, until all the Mezuzahs are mounted.The Brachah/Blessing is said when you are ready to turn the first screw or tap the first nail.The Bracha is as follows:Baruch Ata A-do-nai Elo-heinu Melech Haolam asher kideshanu bemitzvotav vetzivanu likboa mezuza.Translation:Blessed are You, L‑rd our G‑d, King of the universe, who has sanctified us with His commandments and commanded us to affix a Mezuzah.No Bracha/Blessing is recited when affixing a Mezuzah on a room that are not Biblically required to have a Mezuzah.